1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/media/rc/meson-ir-tx.c b/drivers/media/rc/meson-ir-tx.c
new file mode 100644
index 0000000000..6355b79893
--- /dev/null
+++ b/drivers/media/rc/meson-ir-tx.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * meson-ir-tx.c - Amlogic Meson IR TX driver
+ *
+ * Copyright (c) 2021, SberDevices. All Rights Reserved.
+ *
+ * Author: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/of_irq.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+#include <media/rc-core.h>
+
+#define DEVICE_NAME	"Meson IR TX"
+#define DRIVER_NAME	"meson-ir-tx"
+
+#define MIRTX_DEFAULT_CARRIER		38000
+#define MIRTX_DEFAULT_DUTY_CYCLE	50
+#define MIRTX_FIFO_THD			32
+
+#define IRB_MOD_1US_CLK_RATE	1000000
+
+#define IRB_FIFO_LEN	128
+
+#define IRB_ADDR0	0x0
+#define IRB_ADDR1	0x4
+#define IRB_ADDR2	0x8
+#define IRB_ADDR3	0xc
+
+#define IRB_MAX_DELAY	(1 << 10)
+#define IRB_DELAY_MASK	(IRB_MAX_DELAY - 1)
+
+/* IRCTRL_IR_BLASTER_ADDR0 */
+#define IRB_MOD_CLK(x)		((x) << 12)
+#define IRB_MOD_SYS_CLK		0
+#define IRB_MOD_XTAL3_CLK	1
+#define IRB_MOD_1US_CLK		2
+#define IRB_MOD_10US_CLK	3
+#define IRB_INIT_HIGH		BIT(2)
+#define IRB_ENABLE		BIT(0)
+
+/* IRCTRL_IR_BLASTER_ADDR2 */
+#define IRB_MOD_COUNT(lo, hi)	((((lo) - 1) << 16) | ((hi) - 1))
+
+/* IRCTRL_IR_BLASTER_ADDR2 */
+#define IRB_WRITE_FIFO	BIT(16)
+#define IRB_MOD_ENABLE	BIT(12)
+#define IRB_TB_1US	(0x0 << 10)
+#define IRB_TB_10US	(0x1 << 10)
+#define IRB_TB_100US	(0x2 << 10)
+#define IRB_TB_MOD_CLK	(0x3 << 10)
+
+/* IRCTRL_IR_BLASTER_ADDR3 */
+#define IRB_FIFO_THD_PENDING	BIT(16)
+#define IRB_FIFO_IRQ_ENABLE	BIT(8)
+
+struct meson_irtx {
+	struct device *dev;
+	void __iomem *reg_base;
+	u32 *buf;
+	unsigned int buf_len;
+	unsigned int buf_head;
+	unsigned int carrier;
+	unsigned int duty_cycle;
+	/* Locks buf */
+	spinlock_t lock;
+	struct completion completion;
+	unsigned long clk_rate;
+};
+
+static void meson_irtx_set_mod(struct meson_irtx *ir)
+{
+	unsigned int cnt = DIV_ROUND_CLOSEST(ir->clk_rate, ir->carrier);
+	unsigned int pulse_cnt = DIV_ROUND_CLOSEST(cnt * ir->duty_cycle, 100);
+	unsigned int space_cnt = cnt - pulse_cnt;
+
+	dev_dbg(ir->dev, "F_mod = %uHz, T_mod = %luns, duty_cycle = %u%%\n",
+		ir->carrier, NSEC_PER_SEC / ir->clk_rate * cnt,
+		100 * pulse_cnt / cnt);
+
+	writel(IRB_MOD_COUNT(pulse_cnt, space_cnt),
+	       ir->reg_base + IRB_ADDR1);
+}
+
+static void meson_irtx_setup(struct meson_irtx *ir, unsigned int clk_nr)
+{
+	/*
+	 * Disable the TX, set modulator clock tick and set initialize
+	 * output to be high. Set up carrier frequency and duty cycle. Then
+	 * unset initialize output. Enable FIFO interrupt, set FIFO interrupt
+	 * threshold. Finally, enable the transmitter back.
+	 */
+	writel(~IRB_ENABLE & (IRB_MOD_CLK(clk_nr) | IRB_INIT_HIGH),
+	       ir->reg_base + IRB_ADDR0);
+	meson_irtx_set_mod(ir);
+	writel(readl(ir->reg_base + IRB_ADDR0) & ~IRB_INIT_HIGH,
+	       ir->reg_base + IRB_ADDR0);
+	writel(IRB_FIFO_IRQ_ENABLE | MIRTX_FIFO_THD,
+	       ir->reg_base + IRB_ADDR3);
+	writel(readl(ir->reg_base + IRB_ADDR0) | IRB_ENABLE,
+	       ir->reg_base + IRB_ADDR0);
+}
+
+static u32 meson_irtx_prepare_pulse(struct meson_irtx *ir, unsigned int time)
+{
+	unsigned int delay;
+	unsigned int tb = IRB_TB_MOD_CLK;
+	unsigned int tb_us = DIV_ROUND_CLOSEST(USEC_PER_SEC, ir->carrier);
+
+	delay = (DIV_ROUND_CLOSEST(time, tb_us) - 1) & IRB_DELAY_MASK;
+
+	return ((IRB_WRITE_FIFO | IRB_MOD_ENABLE) | tb | delay);
+}
+
+static u32 meson_irtx_prepare_space(struct meson_irtx *ir, unsigned int time)
+{
+	unsigned int delay;
+	unsigned int tb = IRB_TB_100US;
+	unsigned int tb_us = 100;
+
+	if (time <= IRB_MAX_DELAY) {
+		tb = IRB_TB_1US;
+		tb_us = 1;
+	} else if (time <= 10 * IRB_MAX_DELAY) {
+		tb = IRB_TB_10US;
+		tb_us = 10;
+	} else if (time <= 100 * IRB_MAX_DELAY) {
+		tb = IRB_TB_100US;
+		tb_us = 100;
+	}
+
+	delay = (DIV_ROUND_CLOSEST(time, tb_us) - 1) & IRB_DELAY_MASK;
+
+	return ((IRB_WRITE_FIFO & ~IRB_MOD_ENABLE) | tb | delay);
+}
+
+static void meson_irtx_send_buffer(struct meson_irtx *ir)
+{
+	unsigned int nr = 0;
+	unsigned int max_fifo_level = IRB_FIFO_LEN - MIRTX_FIFO_THD;
+
+	while (ir->buf_head < ir->buf_len && nr < max_fifo_level) {
+		writel(ir->buf[ir->buf_head], ir->reg_base + IRB_ADDR2);
+
+		ir->buf_head++;
+		nr++;
+	}
+}
+
+static bool meson_irtx_check_buf(struct meson_irtx *ir,
+				 unsigned int *buf, unsigned int len)
+{
+	unsigned int i;
+
+	for (i = 0; i < len; i++) {
+		unsigned int max_tb_us;
+		/*
+		 * Max space timebase is 100 us.
+		 * Pulse timebase equals to carrier period.
+		 */
+		if (i % 2 == 0)
+			max_tb_us = USEC_PER_SEC / ir->carrier;
+		else
+			max_tb_us = 100;
+
+		if (buf[i] >= max_tb_us * IRB_MAX_DELAY)
+			return false;
+	}
+
+	return true;
+}
+
+static void meson_irtx_fill_buf(struct meson_irtx *ir, u32 *dst_buf,
+				unsigned int *src_buf, unsigned int len)
+{
+	unsigned int i;
+
+	for (i = 0; i < len; i++) {
+		if (i % 2 == 0)
+			dst_buf[i] = meson_irtx_prepare_pulse(ir, src_buf[i]);
+		else
+			dst_buf[i] = meson_irtx_prepare_space(ir, src_buf[i]);
+	}
+}
+
+static irqreturn_t meson_irtx_irqhandler(int irq, void *data)
+{
+	unsigned long flags;
+	struct meson_irtx *ir = data;
+
+	writel(readl(ir->reg_base + IRB_ADDR3) & ~IRB_FIFO_THD_PENDING,
+	       ir->reg_base + IRB_ADDR3);
+
+	if (completion_done(&ir->completion))
+		return IRQ_HANDLED;
+
+	spin_lock_irqsave(&ir->lock, flags);
+	if (ir->buf_head < ir->buf_len)
+		meson_irtx_send_buffer(ir);
+	else
+		complete(&ir->completion);
+	spin_unlock_irqrestore(&ir->lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static int meson_irtx_set_carrier(struct rc_dev *rc, u32 carrier)
+{
+	struct meson_irtx *ir = rc->priv;
+
+	if (carrier == 0)
+		return -EINVAL;
+
+	ir->carrier = carrier;
+	meson_irtx_set_mod(ir);
+
+	return 0;
+}
+
+static int meson_irtx_set_duty_cycle(struct rc_dev *rc, u32 duty_cycle)
+{
+	struct meson_irtx *ir = rc->priv;
+
+	ir->duty_cycle = duty_cycle;
+	meson_irtx_set_mod(ir);
+
+	return 0;
+}
+
+static void meson_irtx_update_buf(struct meson_irtx *ir, u32 *buf,
+				  unsigned int len, unsigned int head)
+{
+	ir->buf = buf;
+	ir->buf_len = len;
+	ir->buf_head = head;
+}
+
+static int meson_irtx_transmit(struct rc_dev *rc, unsigned int *buf,
+			       unsigned int len)
+{
+	unsigned long flags;
+	struct meson_irtx *ir = rc->priv;
+	u32 *tx_buf;
+	int ret = len;
+
+	if (!meson_irtx_check_buf(ir, buf, len))
+		return -EINVAL;
+
+	tx_buf = kmalloc_array(len, sizeof(u32), GFP_KERNEL);
+	if (!tx_buf)
+		return -ENOMEM;
+
+	meson_irtx_fill_buf(ir, tx_buf, buf, len);
+	dev_dbg(ir->dev, "TX buffer filled, length = %u\n", len);
+
+	spin_lock_irqsave(&ir->lock, flags);
+	meson_irtx_update_buf(ir, tx_buf, len, 0);
+	reinit_completion(&ir->completion);
+	meson_irtx_send_buffer(ir);
+	spin_unlock_irqrestore(&ir->lock, flags);
+
+	if (!wait_for_completion_timeout(&ir->completion,
+					 usecs_to_jiffies(IR_MAX_DURATION)))
+		ret = -ETIMEDOUT;
+
+	spin_lock_irqsave(&ir->lock, flags);
+	kfree(ir->buf);
+	meson_irtx_update_buf(ir, NULL, 0, 0);
+	spin_unlock_irqrestore(&ir->lock, flags);
+
+	return ret;
+}
+
+static int meson_irtx_mod_clock_probe(struct meson_irtx *ir,
+				      unsigned int *clk_nr)
+{
+	struct device_node *np = ir->dev->of_node;
+	struct clk *clock;
+
+	if (!np)
+		return -ENODEV;
+
+	clock = devm_clk_get(ir->dev, "xtal");
+	if (IS_ERR(clock) || clk_prepare_enable(clock))
+		return -ENODEV;
+
+	*clk_nr = IRB_MOD_XTAL3_CLK;
+	ir->clk_rate = clk_get_rate(clock) / 3;
+
+	if (ir->clk_rate < IRB_MOD_1US_CLK_RATE) {
+		*clk_nr = IRB_MOD_1US_CLK;
+		ir->clk_rate = IRB_MOD_1US_CLK_RATE;
+	}
+
+	dev_info(ir->dev, "F_clk = %luHz\n", ir->clk_rate);
+
+	return 0;
+}
+
+static int __init meson_irtx_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct meson_irtx *ir;
+	struct rc_dev *rc;
+	int irq;
+	unsigned int clk_nr;
+	int ret;
+
+	ir = devm_kzalloc(dev, sizeof(*ir), GFP_KERNEL);
+	if (!ir)
+		return -ENOMEM;
+
+	ir->reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ir->reg_base))
+		return PTR_ERR(ir->reg_base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -ENODEV;
+
+	ir->dev = dev;
+	ir->carrier = MIRTX_DEFAULT_CARRIER;
+	ir->duty_cycle = MIRTX_DEFAULT_DUTY_CYCLE;
+	init_completion(&ir->completion);
+	spin_lock_init(&ir->lock);
+
+	ret = meson_irtx_mod_clock_probe(ir, &clk_nr);
+	if (ret) {
+		dev_err(dev, "modulator clock setup failed\n");
+		return ret;
+	}
+	meson_irtx_setup(ir, clk_nr);
+
+	ret = devm_request_irq(dev, irq,
+			       meson_irtx_irqhandler,
+			       IRQF_TRIGGER_RISING,
+			       DRIVER_NAME, ir);
+	if (ret) {
+		dev_err(dev, "irq request failed\n");
+		return ret;
+	}
+
+	rc = rc_allocate_device(RC_DRIVER_IR_RAW_TX);
+	if (!rc)
+		return -ENOMEM;
+
+	rc->driver_name = DRIVER_NAME;
+	rc->device_name = DEVICE_NAME;
+	rc->priv = ir;
+
+	rc->tx_ir = meson_irtx_transmit;
+	rc->s_tx_carrier = meson_irtx_set_carrier;
+	rc->s_tx_duty_cycle = meson_irtx_set_duty_cycle;
+
+	ret = rc_register_device(rc);
+	if (ret < 0) {
+		dev_err(dev, "rc_dev registration failed\n");
+		rc_free_device(rc);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, rc);
+
+	return 0;
+}
+
+static void meson_irtx_remove(struct platform_device *pdev)
+{
+	struct rc_dev *rc = platform_get_drvdata(pdev);
+
+	rc_unregister_device(rc);
+}
+
+static const struct of_device_id meson_irtx_dt_match[] = {
+	{
+		.compatible = "amlogic,meson-g12a-ir-tx",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, meson_irtx_dt_match);
+
+static struct platform_driver meson_irtx_pd = {
+	.remove_new = meson_irtx_remove,
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = meson_irtx_dt_match,
+	},
+};
+
+module_platform_driver_probe(meson_irtx_pd, meson_irtx_probe);
+
+MODULE_DESCRIPTION("Meson IR TX driver");
+MODULE_AUTHOR("Viktor Prutyanov <viktor.prutyanov@phystech.edu>");
+MODULE_LICENSE("GPL");